Polishing-wheel-heading machine



Oct. 28, 1930. R. G. PILKINGTON 1,779,633

POLISHING WHEEL HEADING MACHINE I Filed March 19, 1928 5 Sheets-Sheet 1 wuantoz Runner 6. mmnsmu oct-zs, 1930- R G. PILKINGTON \EOIIrs'HING WHEEL HEADING M'AcHINE Filed March 19. 1928 5 Sheets-Sheet 2,

anwidoz ROBERT E PILKINGTON Oct. 28, 1930. R. G. PILKINGTON POLISHING WHEEL HEADING'MACHINE 5 Sheets-Sheet Filed March 19, 1928 FIG. 3.

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POLISHING WHEEL HEADING MACHINE Filed March 19, 1928 5 Sheets-Sheet 4 FIG; 4'.

Oct. 28, 1930. R. e. PILKINGTON POLISHING WHEEL HEADING MACHINE Filed March 19, 1928 5 Sheets-Sheet 5 Fae. 8

. anveutoaa RoaER'r G. PILKING'TON Patented Oct. 28, 1930 UNITED stares PATENT OFFICE ROBERT G. PILKINGTON, F U 'lIC.A,-NEW YORK, ASSIGNOR TO DIVINE BROTHERS COM- 7 PANY, OF UTIGA, NEVJ YORK, A CORPORATION POLISHING--WHEEL-fiEADING MACHINE Application filed March 19,1928. Serial No. 262,766.

My present invention relates to a polishingwheel heading machine, meaning thereby a I o into the glue by the operator pressing the Wheel as he rolls it. "This manual forming of the head upon a polishing-wheel consumes a large amount of time and results in a large proportion of poor or irregular heads on account of the varying care, strength and skill of the operator. 1

The purpose of this invention is to overcome the disadvantages of hand-made heads upon polishing-wheel and to provide a machine for performing the various steps necessary and to perform these steps quicker, better, more economically and with greater regularity and uniformity.

A further purposeis to provide a machine so of the class described wherein means are provided for receiving and rotating a polishingwheel of any varying size within the range of the machine and for quickly placing upon the' periphery of the polishing-wheel a suflicient and uniform layer of glue or other adhesive;

and then Without removing the polishingwheel from the machine; but simply by changing its position in the machine, placing a sufiici'ent and uniform layer ofthe abrasive 40 upon the adhesive covered surface of the polishing-wheel and continuing the supply of said abrasive until a sufficient amount has been placed upon the wheel and then rolling or packing the abrasive into the adhesive with 4 greater pressure if necessary than used in the abrasive supplying step; such packing pressure being readily maintained at an even amount for the whole wheel and continued at a the same pressure for wheelsof the same type; but adapted to be set to give another pressure as may be needed on other types of wheels.

vide a machineof the character described wherein a glue-supplying wheel and an abrasive supplying and packing-wheel arerevolubly mounted in spaced relation with a movable member or members such as rocker arms between said wheels with said rocker arms adapted to removably receive an arbor, carrying the polishing-wheel to be given a head and to have said arms adapted to be swung first towards the gluing-wheel for the polishing wheel to receive the glue therefrom Another purpose of my invention is to pro- 7 and then While the glue is still hot upon the polishing-wheel to have the arms swing away from the gluing-wheel and carry the polish ing-Wheel into engagement with the abrasive supplying-wheel, which wheel also acts as the packing-wheel to pack or press the abrasive into the glue on the polishing-wheel, and after the packing operation has been completed to have the arms adapted to swing to an intermediate position where the arbor canbe removed; the completed polishingwheel removed therefrom and another polishingwheel placed upon the arbor and then the arbor placed in'the machine, whereupon the complete operation is again repeated.

Further purposes of the invention are'to provide improved combinations of the parts and additional parts combining with the machine to perfect its operation, such as a movable mounting for the glue-pot whereby the amount of glue placed uponthe gluing-wheel can be controlled or the glue-pot removed entirely from the glue-wheel as for intervals when the machine is not in operatiom-means for operating and equalizing the amount of glue upon the gluing-wheel, means for regularly and evenly supplying abrasive to the abrasive-supplying wheel and means to recover the abrasive notplaced upon the head of the polishing-wheel and to separate the clean abrasive from the abrasive havingany glue in contact therewith. v I

Fig. 1 is a side elevation of a machine embodying this invention. p

' Fig. 2 is atop or plan view of the machine;

but with the abrasivereceptacle and its sup! 1 port removed.

Fig. 3 is a transverse vertical sectional view through the machine on line 3-3 of Fig. 1.

Fig. 4 is a plan View of the abrasive distributor.

Fi 5 is a central longitudinal sectional view of said distributor together with a part of the rear vibrator wheel.

Fig. 6 is a transverse sectional View of said distributor on line 6-6 of Fig. l.

Pg. 7 is a horizontal sectional view on a line of the counter shaft .65.

Fig. 8 is a detail elevation of the glue distributing means as seen from the left thereof on Fig. 1 and Fig. 9 isa vertical sectional view on line 99 of Fig. 8.

Fig. 10 is a detail sectional view on line 10+10 of Fig. 2 of the weighted lever 96, bracket casing 92 and pawl 124 in operative connection therewith.

Referring to the drawings in a more particular description, it will be seen that the machine comprises a bed-plate supported by suitable legs 21, a platform 22 over a part of the bed-plate and supported thereabove by upright posts 23 and 2e upstanding from the bed-plate 20, two spaced side frame members 25 carrying two spaced rocking arms 26, a gluing wheel 27 and an abrasive supplying and packing wheel 28. revolubly mounted upon the framework of the machine on the opposite sides of said rocker arms and with said rocker arms provided at their upper end with open topped bearings to removably receive an arbor 29 which removably carries the polishing-wheel 30, that is to receive its head of adhesive and abrasive.

Conveniently placed upon the framework of the machine as upon the bed-plate 20 there is provided a main motor 31 adapted through speed reducing device 32 to drive transversely extending shaft 33 at proper speed to rotate the glue wheel 27 and packing wheel 28 by means of chain 34: engaging toothed wheels 35 and 36 respectively mounted upon the shafts carrying the gluing-wheel 27 and the packing-wheel 28.

As the machine is illustrated in Figs. 1 and 2 of the drawings, the gluing-wheel 27 is towards the ri ht hand end of the machine and is revolubly carried by being fixed upon a horizontally arranged transversely extending shaft 37 mounted in bearings 38, provided upon the upper ends of the front and rear posts 39,. and a0 upstanding from the bedplate 20 of the machine. Said shaft projects beyond the rear bearing 38 and is there provided with the'toothed-wheel 35 already mentioned as being driven by main drive-chain 34.

Surrounding the lower portion of the gluing wheel 27 there is provided the glue-pot ll adapted to hold a sufficient supply of liquid glue or other adhesive 12; which glue is kept ff en ly et and. arm d, o p op P- plication by the presence of hot water 43 in the water tank 4A placed below the glue pot 41 with the sides of the tank coming up about the sides of the glue-pot but spaced therefrom and with the tank preferably closed and rendered practically steam tight by the laterally extending flange l5 on the glue-pot resting upon the upper edge of the side walls of the tank 44. The glue-pot flange 45 also serves the purpose of rcmovably supporting the glue-pot in the tank.

The glue-pot and its heating tank 44: is mounted to be bodily moved vertically towards and from the gluing-wheel 27 in order to vary the amount of glue placed upon the gluing-wheel by varying the extent to which the gluing-wheel is immersed in the glue. lVhen the machine is not to be used for some time or when the glue-pot is to be cleaned out, the glue-pot and tank are lowered below the level of the glue-wheel so that the wheel will not stand in the glue and so that the gluepot may be removed if desired.

The giuc-pot and its heating tank are mounted for such vertical movements by the tank l4 beingplaced on top of the movable table 46, which mounted for vertical movement by having relatively long vertical slideways l? at its opposite sides engaging and sliding upon the front and rear posts 39 and 40, which form the frame for carrying the gluing-wheel shaft. Vertical movement is imparted to this table by means of a threaded rod 4E8 fixed to and depending from the table 46, being engaged by a nut l9 surrounding the rod and suitably supported upon the bedplate 20 of the machine with said nut being formed integral with or securely fastened to a bevel gear which in turn is engaged by a bevel gear 51 mounted on a horizontal shaft 52 carried in suitable bearings 53 and 54: with said shaft 52 rotated by a crank arm 55, hav ing handle 56.

To the lower part of the tank 4 1 there is secured a short outwardly extending pipe 57 having at its outer end a T 58, to the lower end of which is attached a valve 59 whereby the water may be withdrawn from the tank. Above the T 58 projects a pipe 66 with a funnel (31 at its upper end for supplying water to the tank.

The two rocker arms 26 are mounted for rocking movement towards the right or towards the left as the machine is seen in Fig. l by said rocker arms being secured to a transversely extending shaft 62 mounted in suitable hearings on the front and rear side frames Below the lower ends of the rocker arms there is mounted in a depending position a segmental gear 63 engaged therebelow by pinion 6% on counter shaft 65 which is mounted in bearings provided in said side frames The front end of this counter shaft has secured thereto a crank arm 66 with a forwardly extending handle 66 hereby in an obv ous mann r man al ta tion of the arm 66 Will impart a partial rotation in the opposite direction to the upstanding rocker arms 26. r

The upper ends of'the rocker arms 26 are each provided with an opened top or roughly V shaped recess 67. At the bottom of said recess is mounted an anti-friction roller 68 and at the opposite sides of said recess there are mounted similar antifriction rollers 69 and '70 respectively. An arbor or shaft 29 of the proper size may now be readily placed into the bearings thus provided at the top of said rocker arms with such arbor or shaft having mounted usually removably thereon the polishing-wheel 80, that is to be given a head by the machine.

A'fter the heading operation'is completed or either step thereof is completed, the arbor and its polishing-wheel maybe as readilyre movedfrom the open topped bearings of the rocker arms. In order to impart one or more layers of glue to the periphery of the polishing-wheel30 the'rocker arms are moved to the right until the periphery of the polishingwheel is brought into sufliciently close contact with the revolving glue-wheel 27 This is done in practice by the operator pressing downwardly on the handle 66 and holding said handle down with sufficient pressure to assure the glue from the glue-wheel being transferred to-the surface of the polishing wheel. v i

The abrasive supplying and packingewheel 28'is mounted the proper distance to the left :1 from the rocker arms 26 by means of a shaft 71 mounted in suitable hearings in the two side frame members 25. To the rearv of the real-frame member said shaft carries its toothed wheel 36 to receive motion from the main drive chain 34. Upon the shaft71 to the rear of the rear frame member 25 is placed a large vibrator-wheel 72 having notches 73 closely spaced along its periphery. To the front of the front: frame member 25 there is placed on this shaft 71 a similar vibrator Wheel 72. Both side vibrator-wheelsare se-' cured to said shaft 71 and operate to give an up and down vibrating motion to the vibrator rod 74. This rod/74E is secured to the bottom of the inclined abrasive distributor 75 towards its lower or right hand end. Towards its upper end the said distributor 75 is'pivotally mounted on a .rod 76 carried by two brackets 7 7 which in turn are mounted. onthe portion of the posts 23, projecting above the platform 22 at the left end of themachine. The detail constructionof this abrasive distributor is'shown inFigs. 4, '5 and '6, which are respectively plan, longitudinal, sectional and transverse sectional views of said distrib utor. It will be seen thatthe distributor is of shovel-like shape having a bottom 78 and an upstanding flange 79 about its forward and rearsides and its upper end. Abrasive from'the abrasive receptacle. 81 gravitates placed atriangular-shaped series of smaller diamond-shaped upstanding pyramids 84. The apex ,ofthe triangular area of these smaller pyramids is in the center of thedistributor and close to the zone'where the abrasivefalls upon the distributor. Thereafter the pyramids are arranged in staggered formation gradually increasing innumber as they. extend downwardly upon the distributor until they cover the full width of'the distributor ona line towards thelower end of the distributor. F arther down upon the distributor are two spaced upstanding ridges 85 and 86, which tend to still further distribute evenly over the whole lower'edge of the distributor the abrasive which has beenseparated into anumber of little streams of abrasive by the guiding action of the pyramids and bythe'vibrating action imparted to the distributor by the up and down motion given by the vibrator-wheels.

The abrasive receptacle 81 is supported in a bracket 87 carried by one of the upstanding posts 23. Below the bracket arms 7 7 there project from the front and rear posts 23 suitable brackets 88 extending tothe right and carrying a shaft 89 which carries an idler I toothed-wheel 90, receiving a loop of the main drive chain 34 to the leftof wheel 36 so that clockwise motion may be imparted to the packing-wheel 28.

Assuming that a polishing-wheel has been placed in the rocker arms as alread described and has received itssupply o glue by being brought into contact with the gluing wheel, the'operator will then move the crank arm 66 in a clockwise direction, moving the polishing-wheel to the left and intoengagement with the wheel 28. It will be understood that when the machine is in operation awidely distributed supply of the abrasive will be continuously dropping from the lower edge of the distributor on to the upper right hand quarter of the-packing-wheel 28,

which part of the wheel is moving downwardly and is constantly being brought into contact with the glue covered surface of the polishing-wheel. Manual pressure of the operator upon the handle 66 is sufiicient to hold the polishing-wheel in contact with the wheel 28,while said polishing-wheel is receiving itsflayers of abrasive. vThe weight of the arms 26 and of the polishing-wheel 30 willalso tend to holdtheIpolishing-wheel in cont-act withthe wheel 28.

After oneor two or perhaps threerotations ion 0f the polishing-wheel 30 upon the wheel 28 the glue on the polishing-wheel becomes fairly well covered with the abrasive and it is desirable to apply greater pressure to the abrasive in order to pack the abrasive down into the layer of glue. By placing greater pressure upon the abrasive and glue upon the polishing-wheel the abrasive is packed down into the glue instead of simply remaining on the surface of the glue allowing more abrasive to be placed upon the polishing-wheel and causing the abrasive to be more nearly uniform throughout the thickness of the head of the polishingwheel. As this packing process continues and the abrasive is pushed down into the glue more abrasive can be added to the surface of the head and some of this subsequently added abrasive can on subsequent rotation of the polishing-wheel be crowded into the thick ness of the head instead of remaining upon its surface. This packing process can be continued until a sufficient amount of abrasive has been incorporated into the head.

It will be understood on the first one or two rotations of the glue covered polishing-wheel against the glue supplying wheel 28 only enough pressure will be placed upon the polishing-wheel to transfer the abrasive from the surface of the wheel 28 to the glue covered surface of the polishing-wheel. Too much pressure at this stage of the proceeding would disturb the glue upon the polishing-wheel or cause the glue to roll up on the polishingwheel ahead of its line of contact with the wheel 28. After a fair coating of abrasive has been placed upon the glue of the polishing-wheel more pressure can properly be used without distorting the head. This first additional pressure can be given by manual pressure upon the handle 66 upon crank arm 66. In order to complete the packing operation however still greater pressure is needed and can be given by the hand upon the handle 66. The means for applying such greater pressure upon the head by pressing the polishing-wheel 30 against the wheel 28 acting as a packing-wheel will now be de scribed.

As already described and as appears in Figs. 1 and 2 of the drawings the swinging movement of the polishing-wheel 30 is effected and the initial pressure of said polishingwheel upon the wheel 28 is brought about by rotation of the shaft bymanual swinging of the crank arm 66 by means of the handle 66*, with said shaft 65 having its pinion 64 in engagement with the segmental gear depending from the shaft 62, which carries the rocker arms 26. As more particularly appears in Fig. 7, which is a horizontal sectional view on the line of the counter shaft 65, there is fixed upon the said shaft near its forward end a ratchet 91. Rotatingly mounted upon the shaft 65 is a bracketlike casing 92, preferably as shown in said Fig. 7 enclosing the ratchet 91 on both sides thereof and provided with a pocket 93 in which is slidingly mounted a pawl 94 for radial movement into or out of engagement with the teeth upon the ratchet 91. Between the pawl and the end of the pocket away from the shaft is interposed a spring 95 operating to normally push the said pawl into engagement with the ratchet. Rigidly secured to the bracket casing 92 is a long radially eX- tending lever 96 upon which is slidingly mounted a weight 97 whereby a variable pressure may be transmitted to the shaft 65 when this weighted lever with the bracket casing is connected to the shaft. Spaced along the lever 96 there is provided a plurality of holes 98 adapted to be engaged by a s ring-pressed pin 99 mounted in the weight 9 When it is desired to vary the pressure, the weight 97 is adjusted along the lever by retracting the pin 99 from one hole by the means of the knob 100 on the forward end of the pin and holding the pin retracted until the weight has been adjusted to desired position and opposite another hole.

In order to hold the weighted lever 96 and the bracket 92 out of rotative engagement with the shaft 65 during the gluing operation and the first part of the abrasive supplying operation, the pawl 94 is held outward from the ratchet 91. This is done by a finger 101 on said pawl extending out through a slot in the forward side of the bracket casing 92 and with the forward end of said finger pivotally connected to a link 102, the farther end of which link is pivotally connected as by headed screw 103 to the lever 104 eccentrically of the axis of said levers pivotal mounting upon the lever 96 and bracket 92 by stub-shaft 105. As the parts are seen in Fig. 7 the lever 104 has been moved to the right to withdraw the pawl 94 from engagement with the pinion 91. This is the position of the parts when the shaft 65 and the rocking arms 26 are being moved simply by the hand strength of the operator. As soon as the operator desires to put additional pressure upon the polishing-wheel, the lever 104 is swung offcenter and towards the shaft 65, which motion aided by the spring 95 moves the pawl 94 into engagement with the ratchet 91. At once the weight of the weighted lever 96 tends to rotate the counter-shaft 65 clockwise and this motion is transmitted to the rocker shaft 62 thereabove to move the rocker arms 26 with the polishing-wheel 30 carried thereon with greater pressure towards the packing-wheel 28. If during any packing process it is desired to increase the pressure, the weight 97 is moved farther out upon the arm 96. After the packing process has been completed, the locking lever 104 is swung back to the position shown in Fig. 7, thereby disengaging the pawl 94 from thepinion and so freeing the shaft 65 from its engagement with the weighted lever. The operator then by proper motion of handle 66 on crank arm 66 swings the rocker arms 26 to intermediate position as shown inFig. 1 whereupon the arbor 29: is lifted from the bearings of the rocker arms and. the polishing-wheel removed from the arbor and set aslde to dry. I

Any loose abrasive upon the wheel 28 not transferred to the polishing-wheel 3O falls from said packing-wheel 28 as it passes downwardly, into the slanting chute 105. This loose abrasive may consist of abrasive supplied to the wheel 28 when there is no polishing-wheel in engagement with the wheel 28 or it may be the abrasive towards the outer edges of the face of said wheel 28, which will not be reached by a polishingwheel of less widththan the width of the polishing-wheel has received nearly its first supply of abrasive. Any glue or adhesive sticking to the descending face of the packing-wheel 28 after it "passes the polishingwheel, willfbe removed therefrom by a spring-pressed blade 106 having its edge pressed against the lower side of the packing-wheel 28. Said blade is mounted by bolts 107 upon themain side frame members 25. The glue and abrasive scraped off by this blade falls into the chute 105. The abrasive and glue from chute 105 may be received into a'proper receptacle and sorted or screened away from the machine, or as shown in Figs. 1 and 2 the chute may deliver this material directly into a barrellike screen 108 rotatably mounted upon the. frame-work of the machine and driven by motor 109. The clean and usable abrasive falls through thesides of this screen and may be returnedfrom time to'timeyto the pail holding the abrasive at the top of the machine. The lumps of glue and abrasive not passing through the screen will be re moved separately and maybe later treated to recover the abrasive. A

To a certain extent the amount of glue placed upon the gluing-wheel and to be transferred to the packing-wheel is determined by the extent to which the gluingwheel 27 is submerged in the glue-pot .41.

of the gluing wheel 27 are extendedupward- 1y above the level of the top of the gluing wheel. In the upper end of these extensions 110 are revolubly mounted the ends of a rod 111 which extends over the top of the gluing wheel and has fixed thereto a bracket 112 which extends to the right of the machine as shown in Figs. 1, 2 and 8. To the outer end of this bracket there is removably secured a brush 113, the bristles 114 ofwhich project down towards the periphery of the gluing wheel. Screw-threaded means are provided for adjusting very accurately the distance or space between the bottomof the brush and the 'periphery of the gluing wheel. Fixed to the extreme forward end of the brush-carrying rod 111 there is a handle 115 extending to the left and a weight 116 extending to the right. 7 The weight in an obvious-manner tends to force the brush towards the gluing wheel, but downward pressure upon the handle 115 may temporarily raise the brush some distance from the wheel.

Back of the handle 115 and weight 116 but still in front of the front extension 110 there is fixedly securedto the rod 111 a bracket 117 projecting to the left of the said rod. Overhanging this bracket 117is located the vertically screw-threaded and split end 118 of an arm 119, formed integral'with'or rigidly attached to the frame extension 110.

In'the vertically screw-threaded aperture in "the end 118 is placed the shank of the adjusting screw 120, havinga large head for manual operation thereof. The lower end of the screw projects downwardly against the upper and outer end of the bracket 117. It will now be seen'that lowering the screw 120 will raise the brush from the gluingwheel. When the correct or desired adjustment is obtained, accidental loosening of the screw 120 is prevented by'tightening up the clamping screw 121 extending'through the two parts ofthe split end 118 of the arm 119. It'will be noted that the screw-threaded adjustment here described for locating the brush will not be interfered with by the temporary lifting ofthe brush by the handle 115. The brush 113 will be of a length greater than the width of the gluing wheel and will operate to distribute the glue evenly and to hold back an lumps of-glue or any excess of glue. 7

Upon the forward post 39 for the gluewheel support there is secured a bracket 122 having a forwardly extending arm 123 to the end of which is pivoted a pawl 124 normally hanging clear of the bracket casing 92 to which the weighted lever 96 is attached. When the operator has finished a packing operation and no longer wishes to have the ports said weighted lever and its attached parts and then he withdraws the pawl 94 from the ratchet 91 by lever 104 as already described.

This pawl 124 supports the weighted lever 96 until the bracket casing is to be again operatively connected to the ratchet 91 when a slight raising of the weighted lever allows the pawl 124 to swing to inoperative position.

What I claim as new and desire to secure by Letters Patent is:

1. In a polishing-wheel heading machine, the combination of a revolubly mounted gluing wheel, means to supply the periphery thereof with glue, a packing wheel revolubly mounted opposite to said gluing wheel, means to supply abrasive to said packing wheel, a frame between said wheels and movable in opposite directions theretowards, means for revolubly and removably mounting a polishing wheel on said frame and means for moving said frame whereby the polishing wheel may occupy an intermediate position out of contact with said glue wheel or said packing wheel or may be moved into engagement with either of said wheels.

2. In a polishing-wheel heading machine, the combination of a revolubly mounted gluing wheel, means to supply the periphery thereof with glue, a packing wheel revolubly mounted opposite to said gluing wheel and on an axis parallel to the axis of said gluing wheel, means to supply abrasive to said packing wheel, a frame between said wheels and movable in opposite directions theretowards,

means for revolubly and removably mounting a polishing wheel on said frame and means for moving said frame whereby the polishing-wheel may occupy an intermediate position out of contact with said glue wheel or said packing wheel or may be moved into engagement with either of said wheels.

3. In a polishing-wheel heading machine, the combination of a revolubly mounted gluing wheel, means to supply the periphery thereof with glue, a packing wheel revolubly mounted opposite to said gluing wheel, means to supply abrasive to said packing wheel, a frame between said wheels and movable in opposite directions theretowards, means for revolubly and removably mounting a polish ing wheel on said frame, means for moving said frame whereby the polishing wheel may occupy an intermediate position out of contact with said glue wheel or said packing wheel or may be moved into engagement with either of said wheels and means for increasing the pressure of the polishing wheel upon the packing wheel.

4. In a polishing-wheel heading machine, the combination of a revolubly mounted gluing wheel, means to supply the periphery thereof with glue, a packing wheel revolubly mounted opposite to said gluing wheel, means to supply abrasive to said packing wheel, a

frame'between said wheels and movable in opposite directions theretowards, means for revolubly and removably mounting a polish ing wheel on said frame, means for moving said frame whereby the polishing wheel may occupy an intermediate position out of contact with said glue wheel or said packing wheel or may be moved into engagement with either of said wheels and additional means operatively connectible to said frame for swinging said frame and therewith the polishing wheel with increased pressure towards the packing wheel.

5. In a polishing-wheel heading machine, the combination of a revolubly mounted gluing wheel, means to supply the periphery thereof with glue, a packing wheel revolubly mounted opposite to said gluing wheel, means to supply abrasive to said packing wheel, a frame between said wheels and movable in opposite directions theretowards, means for revolubly and removably mounting a polishing wheel on said frame, means for moving said frame whereby the polishing wheel may occupy an intermediate position out of contact with said glue wheel or said packing wheel or may be moved into engagement with either of said wheels and means for increasing in a varying amount the pressure of the polishing wheel upon the packing wheel.

6. In a polishing-wheel heading machine, the combination of a packing wheel revolubly mounted, means to supply abrasive to said packing wheel, a frame opposite said packing wheel and movable towards and from said wheel, means for revolubly and removably mounting a polishing wheel on said frame, means for moving said frame whereby the polishing wheel may occupy a position out of contact with said packing wheel or may be moved into engagement with said packing wheel, and means forincreasing the pressure of the polishing wheel upon the packing wheel.

7. In a polishing-wheel heading machine, the combination of a packing wheel revolubly mounted, means to supply abrasive to said packing wheel, a frame opposite said packing wheel and movable towards and from said wheel, means for revolubly and removably mounting a polishing wheel on said frame, means for moving said frame whereby the polishing wheel may occupy a position out of contact with said packing wheel or may be moved into engagement with said packing wheel, and further means operatively connectible to said, frame for increasing the pressure of the polishing wheel upon the packing wheel.

8. In a polishing-wheel heading machine, the combination of a packing wheel revolubly mounted, means to supply abrasive to said packing wheel, a frame opposite said packing wheel and movable towards and from said wheel, means for revolubly and removably mounting a polishing wheel on said frame, means for moving said frame whereby the polishing wheel may occupy a position out of contact with said packing wheel or may be moved into engagement with said packing wheel, and means for increasing in a Varying amount the pressure of the polishing wheel upon the packing wheel. I

In witness whereof I have affixed my signature, this 17th day of February, 1928.

ROBERT G. PILKINGTON. 

